I Wrote the DOT about the same kind of problem with my LX 470:
2004 LX470 AHC (Automatic Height Control Failure)!
As of January 22, 2008, the AHC failed.
The LX470 rides very, very roughly, even though one maybe driving on a smooth road. On occasion, the car will even tilt to one side while being driven down the road. The car sits very low and the height will not come up to the "N" level. The car often stays in the Low position when at highway speed. The "AHC OFF LIGHT" keeps flashing. Sometimes the car will come up a bit, but then it goes back down. If the light indicates the car is in the "N" position, it is NOT. It is in the Low position. Again, the car does not come up to “N” even when the car is at speed. Often, the car’s rear end will be all the way down LOW and the front end in the “H” position. This configuration puts the headlights pointing very high. (see photographs)
When the car is in the LOW position, as it is presently in the rear, there is very little suspension travel and virtually no way to control the vehicle in a sudden maneuver. In addition, the car will oscillate from front to back as if it were a boat going into waves. The front end will go up to the High position while going at speed, but the indicator light may return to the Normal Position even though the car stays in the high position. Though, one must say, presently there is little, which is NORMAL about the way the LX470 drives.
I called Lexus Customer Service in California. I got a very polite person, but no real explanation or help. I now have an appointment with the Local Lexus Dealer to get the car repaired.
A service manager at a Lexus dealership said, the suspension system failure could be due to salty, slushy roads ruining the sensors. If this is the case, the LX 470 Lexus should not be driven in the winter.
Nevertheless, whatever the reason for the suspension system failure, I feel this type of suspension system failure is an "extreme safety hazard" and inexcusable. These cars should be RECALLED before someone gets injured or killed. Should a suspension failure occur at speed in or out of traffic, the car could easily go out of control.
(A repair was completed, by the install of a new sensor)
aWill